The present invention relates to a controller and method of operating a climate control system including a primary and a secondary heating and cooling source with humidity control. More specifically, the present invention is a controller and method of providing heating and cooling to a zoned residence or building, from a primary source of heat, such as a radiant heating system, and a secondary source of heat, such as a forced air HVAC system. The HVAC system preferably provides primary and secondary cooling as well as humidity control.
Many small businesses and homes utilize a zoned radiant heating system to heat the individual zones during periods of cold outside temperatures, such as during the winter months. In a radiant heating system, a supply of heated water is distributed through a series of heat exchanging pipes positioned throughout the heating zone. For example, a radiant heating system can include radiant floor pipes and baseboard mounted radiators which transfer heat from the supply of heated water to the open environment being controlled.
In a zoned radiant heating system, a controller receives heating demand signals from individual zone thermostats and controls the operation of the main boiler, injection system, a number of water circulators and series of zone controlling devices such as valves or circulators to supply the heated water from the boiler to the individual zones requiring heat. Although radiant heating systems are effective at maintaining a very constant temperature within a heating environment, radiant heating systems often suffer from the inability to quickly heat a room upon a sudden demand for heat, such as when the outside temperature drops dramatically, when the radiant heating system is initially turned on, or when a window has been left open and the temperature within one of the heating zone drops dramatically.
In a small business or residence that utilizes radiant heating, a forced air HVAC system that includes a full zone venting infrastructure and numerous zone dampers to control the flow of air into the zones is installed to provide air conditioning. The HVAC forced air system includes its own separate controller that receives cooling demand signals from the zone thermostats such that the forced air controller controls the operation of the chiller and the opening and closing of the zone dampers to provide cooling to the residence as required. Typically, the control unit for the forced air HVAC system is separate from the control unit for the radiant heating system. Since the controllers of the two systems operate independently, the combined climate control system includes a switch that allows the homeowner to select either the heating and cooling functions.
In a residence or small businesses that has both a radiant heating system and a forced air HVAC system, the forced air HVAC system is used exclusively for cooling. Although it is used only for cooling in this type of application, the forced air HVAC system can also include a heat source to provide heat to the residence. Since radiant heating is a more preferred type of heat, the HVAC forced air system normally does not utilize the forced air heating capabilities. One primary reason for this is the inability for the forced air controller to communicate and coordinate the heating function with the controller for the radiant heating system.
As discussed above, one draw back of a radiant heating system is the inability of the radiant heating system to quickly elevate the temperature in the building to the desired temperature upon a sudden demand for heat. Although the radiant heating system is able to elevate the temperature in a building a few degrees in an acceptable amount of time, situations which require a large temperature rise require an increased amount of time compare to a forced air heating system.
Therefore, it is an object of the present invention to provide a controller that is capable of simultaneously operating both a radiant heating system and a forced air HVAC system based on signals received from a series of zone thermostats. Further, it is an object of the present invention to operate the combined radiant and forced air HVAC systems in a manner such that the forced air system is used to supplement the heat provided by the radiant system when the radiant system is unable to meet the heating demand within a preselected time period. In addition, it is an object of the present invention to operate both the primary and secondary heating and cooling system, along with humidity, from one thermostat per zone.
The present invention is a controller for a climate control system that includes a primary heat source and a forced air system that provides a secondary heat source, primary and secondary cooling, and humidity control. The controller of the present invention controls the operation of the primary heat source, the secondary heat source and the cooling unit such that the single controller can operate the three separate systems in an efficient manner to control the temperature within a residence or small business.
The controller of the present invention is operatively connected to the primary heat source and operates the primary heat source to provide heat to the residence. Preferably, the primary heat source is a zoned radiant heating system that utilizes a supply of heated water to independently heat each of the zones based upon a heat demand signal from a zone thermostat. The controller of the present invention is coupled to the boiler, a plurality of water circulators and a zone control devices such as a valve or circulator for each zone such that the controller can selectively divert the supply of heated water to any zone issuing a heat demand signal.
In addition to its connection to its primary radiant heating system, the controller of the present invention is connected to a secondary heat source. In the preferred embodiment to the invention, the secondary heat source is a forced air HVAC system. The forced air HVAC system includes both a heating and a cooling unit such that the forced air system can supply both cooled and heated air to each of the zones in the residence. The forced air HVAC system includes a plurality of zone dampers that can be opened and closed by the controller to divert the heated or cooled air from the forced air system into the selected zones. Additionally, the forced air system can include a humidifier controlled by the controller of the present invention. Thus, the controller of the present invention can supply humidity to selected zones within the residence.
In accordance with the present invention, the controller initially operates the radiant heating system to satisfy any heat demand signal received from one of the zones. Upon supplying heated water from the radiant heating system to a zone demanding heat, the controller monitors the continuous period of time a heat demand signal is generated from that zone. If the primary, radiant heating system is unable to satisfy the heat demand signal within a field selected period of time, the controller activates the secondary forced air heating system to supplement the heat being supplied by the primary heating system. The period between activation of the primary heat source and the secondary heat source is selectable by the user.
The controller of the present invention also controls the operation of the cooling unit within the forced air system. If any one of the individual zones generates a cooling demand signal, the controller activates the first condenser coil in the cooling unit and the circulating fan for the forced air system. Upon activation of the cooling unit, the controller monitors the continuous amount of time a cooling demand signal is received that zone. If the continuous period of time the cooling demand signal is generated exceeds a preselected time period, the controller activates a supplemental cooling source, such as a secondary condenser coil in the cooling unit, to aid in cooling the individual zone requesting cooling.
As described above, the controller of the present invention is able to simultaneously control the operation of a primary heat source and a secondary heat source such that the secondary heat source can be operated to supplement the heat being supplied by the primary heat source. According to the invention, the primary heat source is preferably a radiant heating system, while the secondary heat source is a forced air system that also includes a cooling unit. Thus, the single controller of the present invention is able to coordinate the operation of two otherwise independent heating systems such that the heating systems can operate effectively together to provide the most efficient, comfortable, and effective heating of the zones in a residence.
Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings.